The present invention is directed to a method and apparatus for processing substrates, particularly for equipping the substrates with electrical components.
In the automatic equipping of substrates (for example, printed circuit boards or ceramic substrates) with SMD (surface mounted device) components, the individual components are taken from a magazine or a delivery means with an equipping head and are then positioned on the substrate in a predetermined orientation. The substrates are thereby taken from a magazine and transported onto a processing position in a first automatic processing unit. In this first automatic processing unit, for example, adhesive is applied to the locations of the substrate at which components are to be placed in a second automatic processing unit. The substrates are transported to this second automated processing unit with a conveyor means.
The knowledge of the position of the substrate is thereby required for the exact positioning of components. To that end, position markings (for example, crosses) are applied on the substrate that are registered in the automatic processing unit by a camera and that are interpreted with respect to their relative position relative to the automatic processing unit in an image evaluation unit that follows the camera.
The plurality of circuits can be provided on a substrate, these in turn respectively having circuit markings that are measured in order, for example, to reduce the influence of warping in the substrate on the equipping position. Additionally, non-functioning circuits are marked by function markings, what are referred to as ink points. As a result thereof, the camera with the following image evaluation in it recognizes the faulty circuit and an equipping with components does not ensue.
When complex circuits having many different types of components are equipped, then a plurality of processing stations are arranged in a line, the substrates being conveyed between them. The position markings, the circuit markings and the function markings are thereby measured and evaluated in every processing station. This requires a correspondingly large time expenditure.
In automatic equipping units of the FUJI Machine Company, however, it is known to transport the substrates on workpiece carriers that are provided with exact fixing means. As a result thereof, the measuring of following automatic equipping units is eliminated. However, a great plurality of expensive workpiece carriers must be kept on hand.